The present invention relates to an interlocking, adaptable, metal truss construction useful for floor joists, roof trusses, roof rafters, wall studs, beams, posts, chords, and lintels and relates to a novel chord member consisting of interlocked two or more chord tubes for use in said truss construction. More specifically, the truss construction finds particular application in metallic light-weight structural framing and modular concrete forming.
Open-web floor joists and roof rafters having wooden upper and lower wooden chords joined at equispaced intervals by U-shaped metal diagonals are known. The truss construction has the advantage over solid wooden joists and rafters of permitting utilities such as plumbing, electrical wiring and ventilation ductwork to freely pass through open spaces in the trusses, whilst using up to thirty percent less material.
Light-weight structural framing systems comprised of solid metal channel and I-beam studs and top and bottom horizontal tracks and bridging channels joined by sheet metal angle brackets and gussets using sheet metal screws or by tack welds are also known. The webs of the channel and I-beam joists are closed, necessitating the costly drilling or cutting of the webs by skilled workmen to allow utilities to pass through.
E. J. W. Ragsdale, in U.S. Pat. No. 1,924,881 discloses an open trussed girder having hollow chords of generally channel form and three-sided hollow web members secured to the inner sides of said hollow chords portion by means of integral extensions. The integral extensions are bent to fit against the corresponding walls of the hollow chords.
U.S. Pat. No. 3,152,671 issued to A. M. Mallory, Jr. teaches structural truss members having C-shaped angular chord members carrying protruding end attachment plates. One embodiment describes truss members provided with upper and lower spans each span comprising a plurality of segmental chords. The latter are C-shaped in cross section and longitudinally disposed in end to end abutment to form the upper and lower linear spans of the trusses.
In U.S. Pat. No. 5,761,873 issued to J. Slater, there is disclosed a web, beam and frame system for a building structure. The system comprises the load bearing members, i.e. beams, wherein each beam is assembled to include a pair of hollow metal cords of equal outer cross-section, and a metal web shaped to provide a pair of jigs which pre-locate the chords parallel to one another. Each web has a plurality of holes for installation of the fasteners therethrough and into the chords.
In U.S. Pat. No. 5,463,837, D. J. Dry discloses a new and improved metal truss wherein the bottom and top chord members are of a substantially uniform shape and cross-section. A radiussed hemmed edge is provided along both legs of the truss chord to protect workers from injury. One or more stiffening ribs are formed in the side walls of the chord members.
J. L. Larson in U.S. Pat. No. 5,865,008 provides a structural shape for use in frame construction which is illustrative of the state of the art. The chord member utilized in the structural shape defines a generally U-shaped cross-section forming a narrower central section with upper and lower portions being of a greater width. An upper, inwardly extending flanged portion has a distance between the legs of the chord which is greater than the distance between the narrow central section legs, thereby enabling easier installation of webs or struts into the chord members.
In my co-pending application Ser. No. 09/105986, there is described a metal truss for use as floor joists, wall studs, and roof trusses. The metal truss comprises a pair of parallel, spaced-apart, elongate metal chord tubes, and a plurality of diagonal metal members equispaced along said pair of tubes for interconnecting the chord tubes. The diagonal members are arranged in V-shaped pairs with a diagonal member of each pair being attached alternately on opposite sides of the chord tubes using fasteners. The metal truss construction further extends to the inclusion of thermal break pads formed of a heat insulating material which are installed between the diagonal members and the elongated metal chord tubes.
In another co-pending application, Ser. No. 09/320,631, a specific embodiment of the invention provides a metal roof truss comprising a pair of parallel, spaced apart, generally U-shaped elongate chord members each having a longitudinal axis, a plurality of alternating diagonal bracing members securely fastened by means of fasteners within said chord members at predetermined intervals and angles. The diagonal bracing members define a generally U-shaped section consisting of a central web and depending side arms, each said side arm having an inwardly extending bent or curved lip portion along the distal edges thereof. The elongate chord members are maintained by said diagonal bracing members in a reinforced, fixed, rigid, spatial relationship one to another.
The disclosures of the above-referenced co-pending applications are hereby incorporated by reference.
It is an objective of the present invention to provide a novel, chord member comprising at least two interlocked chord tubes, said chord member being used in the construction of novel metal truss assemblies, particularly for floor joists, roof trusses, roof rafters, wall studs, beams, posts, chords and lintels. The chord tubes are elongate, of a generally U-shaped cross-section and are characterized in having depending, crenellated side arms which define a plurality of identical, opposed, generally rectangular, longitudinal, reinforcing ribs defining elongated recesses therebetween extending along the length thereof. The interlocking of adjacent chord tubes to form the chord member is effected by having equisized and equispaced ribs on the depending side arms of one chord tube being adapted to fit into the spaces formed between adjacent equisized and equispaced ribs defined on the depending side arms of adjacent chord tubes. Fasteners located at predetermined intervals along the depending side arms of the interlocked chord tubes further secure adjacent chord tubes one to another.
It is a further objective of the present invention to provide metal truss assemblies utilizing the interlocking chord member of the invention to increase the structural strength thereof. Reinforcement and augmentation of the structural strength of the metal truss structure is attained by the expedient of providing the increased number of chord tubes forming the chord member, and the provision of a plurality of reinforcing, or stiffening, ribs on the depending arms of each chord tubes. Additionally, whilst all of the chord members utilized in the metal truss assemblies may not incorporate an interlocked chord member, preferably the non-interlocked chord members, that is to say the chord tubes, are provided with one or more identical, opposed, longitudinal reinforcing ribs along the length of the depending side arms thereof.
It is yet still another objective of the invention to provide novel metal truss structures utilizing chord members formed of the interlocking chord tubes which may be rapidly and cost effectively assembled either at a factory installation or at a construction site, and which may be incorporated into a building system.
In its simplest embodiment, the invention comprises a metal chord member for use in a building system which consists of two or more interlocking chord tubes wherein each chord tube comprises an elongate member having a generally U-shaped cross-section forming a central web and depending side arms, each of said side arms forming a plurality of identical, opposed, outwardly extending, longitudinal, generally rectangular ribs along the length thereof defining elongated recesses therebetween, said ribs being equisized and equispaced and positioned in a predetermined spatial relationship one to another whereby the ribs on one chord tube are adapted to interlock into the elongated recesses defined between adjacent ribs on adjacent chord tubes.
In the broadest embodiment pertaining to a metal truss structure, the invention comprises at least one elongate interlocking, first metal chord member which consists of two or more interlocking chord tubes wherein each chord tube comprises an elongate, member having a generally U-shaped cross-section said chord tube forming a central web and depending side arms, each of said side arms forming a plurality of identical, opposed, outwardly extending, longitudinal, generally rectangular ribs along the length thereof, defining elongated recesses therebetween, said ribs being equisized and equispaced and positioned in a predetermined spatial relationship one to another whereby the ribs on one chord tube are adapted to interlock into the mating recesses defined between adjacent ribs on adjacent chord tubes, and a second, spaced apart chord member, or chord tube, which chord members, or chord tubes, are interconnected by means of bracing members having particularly angled configurations. Preferably, said bracing members would define a generally U-shaped cross-section having inwardly extending curved lips formed along the upper edges of the side walls thereof. Also in this the broadest embodiment, the second chord member would preferably comprise an identical chord member to said first chord member.
The invention further extends to a novel metal truss assembly consisting of a floor joist, a roof truss and wall studs, and wherein said truss assembly incorporates the interlocked chord tubes as a chord member, preferably a chord member utilized in the construction of a floor joist, a roof truss or wall studs. Additionally, at least one elongate stiffening rib extending longitudinally along the length of each of the depending side arms of the generally U-shaped chord tubes is provided on the chord members utilized in the construction of roof truss and wall studs. The most preferred embodiment of the metal truss assembly incorporates a floor joist having upper and lower chord members each consisting of three interlocked chord tubes, a roof truss having upper chord tubes wherein the depending side arms define two identical, longitudinal, generally rectangular reinforcing ribs in predetermined spacial relationship along the length thereof, and a lower chord tube defining one identical, longitudinal, generally rectangular rib, said upper and lower chord tubes being interconnected by means of a pair of opposed, angled diagonal chord members, and the wall studs include chord tubes defining one longitudinal reinforcing rib along the depending side walls thereof, which rib extends along the length of said chord tube.
Broadly stated, the metal truss assembly comprises a roof truss consisting of a pair of parallel, spaced apart, generally U-shaped, elongate chord tubes interconnected by means of a pair of angled, diagonal chord tubes at the outer ends thereof, said chord tubes defining a central web and depending side arms, each of said arms forming at least one identical, opposed, longitudinal, generally rectangular ribs along the length thereof defining elongated recesses therebetween, and a plurality of bracing members alternately positioned between and securely affixed by means of fasteners within said chord members, said bracing members being positioned between said chord tubes in a vertical orientation or a diagonal orientation, said bracing member having a generally U-shaped section, and wherein said elongate chord tubes are maintained by said bracing members in a reinforced, fixed, rigid, spatial relationship one to another; a wall stud consisting of two spaced-apart, parallel, elongate chord tubes each having a U-shaped cross-section with a central web and depending side arms, each of said side arms forming at least one identical, opposed, longitudinal, generally rectangular rib along the length thereof defining elongated recesses therebetween, and a plurality of bracing members alternately positioned between and securely affixed by means of fasteners within said chord tubes, said bracing members being positioned between said chord tubes in a diagonal orientation said bracing member having a generally U-shaped sections, and wherein said elongate chord tubes are maintained by said bracing members in a reinforced, fixed, rigid, spatial relationship one to another; and a floor joist consisting of two spaced-apart, parallel, elongate, chord members, at least one of said chord members comprising two or more interlocked chord tubes, said chord tubes defining a central web and depending side arms, each of said arms forming a plurality of identical, opposed, generally rectangular ribs longitudinally along the length thereof defining elongated recesses therebetween, and a plurality of bracing members alternately positioned between and securely affixed by means of fasteners within said chord members, said bracing members being positioned between said chord members in a diagonal orientation, said bracing member having a generally U-shaped section and wherein said elongate chord members are maintained by said bracing members in a reinforced, fixed, rigid, spatial relationship one to another.
Preferably, the bracing members utilized in the floor joist, roof truss and wall studs form along the length of both side walls of said generally U-shaped section of the bracing members, at the outermost distal portion of said side walls, an inwardly extending curved lip portion.
Preferably, the fasteners are selected from spot welds, clinging, self-tapping screws, rivets, and nut and bolt assemblies. The most preferred fastener would be a spot weld.
Advantageously, in providing, in combination, the interlocked chord members, together with bracing members having a generally U-shaped cross-section defining an inwardly extending lip along the distal edge portion of the side walls thereof, not only may the fasteners be easily placed to secure said bracing members within said chord members, thus facilitating ease and thus cost effectiveness of fabrication, but by the provision of the interlocked chord members unexpectedly high mechanical strength and rigidity with resistance to lateral deflection may be obtained.